The present invention relates to fabric softener compositions adapted for the use in the rinse cycle of a laundering process and in particular to highly concentrated fabric softener compositions which are easily dispersed in water when used, particularly in laundry machines having automatic dispensing mechanisms.
Compositions containing quaternary ammonium salts having at least one long chain hydrocarbyl group are commonly used to provide fabric softening benefits when employed in a laundry rinse operation; for example, see U.S. Pat. Nos. 3,349,033; 3,644,203; 3,946,115; 3,997,453; 4,073,735 and 4,119,545.
For most aqueous softener compositions containing cationic quaternary ammonium compounds as active ingredients, the concentration of such cationics has, in general, been limited to the range of about 3 to 6% by weight (see U.S. Pat. No. 3,904,533 and U.S. Pat. No. 3,920,565). Such a low concentration is generally necessitated by the fact that cationics form gels in water systems at concentrations at above about 8%, and while the use of electrolytes to lower the viscosity of such compositions is known (see in particular U.S. Pat. No. 4,199,545), such electrolytes are far from satisfactory. From a functional point of view, the electrolytes often do not perform as required particularly at concentrations of the cationics in the neighborhood of about 12-15%. Further, while the performance of the electrolytes may mitigate some of the gelling problem, their use is far from satisfactory in providing a highly concentrated aqueous system of cationics which does not gel or severely change in viscosity within the usual range of temperatures encountered in the handling thereof, for example 0.degree. F. (about -18.degree. C.) up to about 140.degree. F. (about 60.degree. C.) or in the dispensing from washing machines.
In the ordinary use of European household automatic washing machines, the user places the rinse cycle fabric softener in a dispensing unit (e.g. a dispensing drawer) of the machine. Then, in the operation of the machine, during the rinse cycle, the softener composition is subjected to a stream of cold water to transfer it to the drum. In winter, when the soften composition and the water fed to the dispenser may be especially cold, there can be problems in that some of the composition is not flushed completely off the dispenser during operation of the machine, and a deposit of the composition may build up with repeated wash cycles, so that it may become necessary for the user to flush the dispenser with hot water. This problem can be particularly severe for highly concentrated softener formulations because of the aforementioned gelling problem and also when a nonionic surfactant is present with the cationic softener since there is a tendency for the viscosity of the nonionic to increase when mixed with cold water forming a gel.
In British application 2053249A published Feb. 4, 1981, there are disclosed cationic fabric softening compositions containing 15 to 60% by weight of cationic softener, 25 to 75% by weight of an aqueous medium and 0.5 to 40% by weight of a specified water soluble polymer.
In U.S. Pat. No. 4,351,737 concentrated fabric softeners are described containing both cationic and non-ionic softeners and a non-ionic dispersing agent along with a solvent mixture of a C.sub.1 to C.sub.3 alkanol and a liquid glycol, polyglycol or an alkyl ether thereof. Hexylene glycol is not disclosed.
It has now been found that the dispersibility in cold water and the flow from automatic dispensers, even in highly concentrated, nonionic surfactant-containing liquid fabric softener compositions can be improved considerably by replacing part or all of the conventional liquid carrier of the non-aqueous liquid softener composition by hexylene glycol.